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That comes from updating the >> extra_bw of the CPUs once per root domain, not once per task. But the >> longest section with interrupts disabled grows with the number of >> deadline tasks. I do not think that is a step forward for a real-time >> class. > > This is domain rebuild? Do we really care about performance there? My worry is not performance, but rather the contribution of this "iteration on all tasks" on the irqoff latency of the system, which is relevant for RT. What I don't know: 1) is 10k deadline tasks something that we should consider as realistic for sched deadline, or it's way beyond practical scale ? 2) is a irqoff latency of 1.2ms (rather than 0.3ms) something which is relevant in terms of irq off latency on a preempt rt kernel, or is it in the noise ? 3) are those domain rebuild expected to happen with a live RT workload, or are those operations expected to never happen on a RT system under real-time constraints ? Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com